1. Field of the Invention
The present invention relates to a chassis structure, an optical scanning device, and an image forming apparatus.
2. Description of the Related Art
In electrophotographic image forming apparatuses, optical image information is formed on a previously uniformly charged image bearer, such as a photoconductor, by an optical scanning device so that an electrostatic latent image is obtained, the electrostatic latent image is visualized by using toner from a developing device, a visible image is transferred onto a recording medium, such as a transfer sheet, directly or via an intermediate transfer member, such as an intermediate transfer belt, an unfixed toner image on the recording medium is fixed by a fixing device that uses pressure, heat, and/or the like, whereby an image is formed. The optical scanning device uses an LD array (hereinafter, referred to as the LDA), a vertical-cavity surface-emitting laser (hereinafter, referred to as the VCSEL), or the like, and thus the quality/the image quality has been enhanced by increasing channels of luminous points.
It is already known that, in this type of optical scanning device of the image forming apparatus, faulty images (image voids, or the like,) occur due to contamination of an optical element, or the like, with dusts, foreign matters, or the like.
To solve such a problem, there is a known structure in which a sponge member, which is a seal member, is compressed and installed between an optical housing and a cover member that covers an opening of the optical housing, whereby the entry of a foreign matter, or the like, is prevented (for example, see Japanese Laid-open Patent Publication No. 2014-12368).
However, the optical scanning device of the image forming apparatus that is described in Japanese Laid-open Patent Publication No. 2014-12368 has a problem in that, as the seal member is complicated or is divided into multiple pieces by necessity, the yield rate of sheet materials is low and the costs are increased. Furthermore, as seal members have a joint line, a clearance occurs at the joint line, which results in a problem of a reduction in the sealing capability. Furthermore, there is a possibility that a sponge member is fragmented due to hydrolysis that is caused by water (moistures), or the like, with the passage of time, and the fragmented sponge member enters the image forming apparatus as a foreign matter. As a result, there is a problem of the occurrence of faulty images, such as image voids.
There is a need to provide a chassis structure that has a simple configuration and that ensures the sealing performance of a chassis with the passage of time.